Graham:
You are correct of course that a longer moment arm (i. e., all the way
forward) would require less mass to balance the tailplane but the density of
the material (to which you allude in mentioning lead and tungsten - depleted
uranium's greater density would be even better) simply affects the size of
that mass, not its "weight."
In order to take advantage of the higher density of an alternate material
(should anyone care to do so) the axial dimension of the counterweight must
be reduced, the diameter kept at the maximum permitted for clearance at the
top and bottom of its movement range, and the counterweight must be mounted
full forward. That would result in a slight reduction of the mass required
for balance.
Lead is cheap and the same mass counterweight would be about three fourths
as long as the steel weights supplied with the kit. Tungsten is very
expensive and impossible to machine with conventional methods (gold has
about the same density but is very easy to machine), but would reduce the
length by a bit more than half. Most of us can't afford that much gold or
tungsten nor do we have access to depleted uranium :)
Best regards,
Rob Housman
Europa XS Tri-Gear A070
Airframe complete
Irvine, CA
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]On Behalf Of Graham Singleton
Subject: Europa-List: Tailplane Balance
<graham@gflight.f9.co.uk>
>My weights are all the way rearward. I then drilled all around the
>forward most weight with ever increasing drill bit sizes, until the
>tailplane came into balance...
>
>--
>Rocketman -
If the weights are all the way forward less weight will be needed. In fact
it would be even lighter if lead or tungsten was used. All about the moment
arm.
Graham
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